In the prior art, applicant is aware of U.S. Pat. No. 5,215,025 which issued Jun. 1, 1993 to Talmor for a Boat, in which it is taught to provide collapsible fuel bags positioned within water ballast compartments so that, as fuel is consumed from the collapsible fuel bags, an increased amount of ballast water can be added to maintain the boat in its a ballasted condition. Further, applicant is aware of U.S. Pat. No. 5,325,804 which issued Jul. 5, 1994 to Schneider for a Fuel-Efficient Watercraft wherein a watercraft is claimed as including a self-compensating fuel tank which includes a fuel bladder disposed inside a rigid enclosure. A plurality of openings disposed in the rigid enclosure permit water to flow through the openings and include the enclosure as the water occupied by the fuel bladder decreases, or out of the enclosure as the volume occupied by the fuel bladder increases, whereby a total volume of fluid inside the rigid enclosure can remain substantially constant.
What is neither taught nor suggested, and which is one object of the present invention to provide, is the provision of additional bladders within the water ballast tank for providing, for example, fresh water supply and for providing a separate repository for grey water in part recapturing the fresh water once used by occupants of the vessel. It is a further object of the present invention to provide a plurality of flexible bladders which may be simply anchored within a water ballast container mounted in the hull of the vessel wherein the bladders may variously hold a gas such as air to assist in compressing, that is, slightly pressurizing, the contents of the remaining bladders which may include bladders having motor fuel and fresh water so as to assist in the dispensing of the fuel and water from those bladders.